Lagging for boiler furnaces



Jan. 5, 1932. .1. E. MUHLFELD LAGGING FOR BOILER FURNACES Filed April 11, 1928 2 Sheets-Sheet Jan. 5, 1932. J. E. MUHLFELD LAGGING FOR BOILER FURNACES Filed April 11, 1928 2 Sheets-Sheet 2 II/Illllllll Svwamtoz Mil/24%; 93 M GEM/me Patented Jan. 5, 1932 UNT2E- srarss' JOHN E. MUHLFELD,OF SC ARSDALE, YORK income non BOILER summons Application filed April 11,

This invention relates to lagging for boiler furnaces, and more particularly to insulating and fire proofing means for furnaces of that type in which the side walls arecomposed of water conduits directly subject to the high temperature gases and products of combustion in their passage through the coma bustion chamber of the furnace. 7

It is a more particular object of my in:

10 vention to provide lagging or insulating means which will be particularly efi'icient and serviceable in its application to locomotive boiler furnaces of that type which have re cently been adopted by several of the railroads wherein the opposite side walls of the furnace firebox consist of vertical water conducting tubes extending between upper and lower drums and'which is primarily characterized by the provision of an inner high 29 temperature resisting metallic covering in contact with the metal tubes and whereby an absolutely air and smoke tightclosure of the opposite sides of the furnace may be obtained. The same structure may also be utilized at the ends of the furnace and is applicable to furnaces having a foundation ring instead of the lower pair of drums.

It is also another object of my invention to provide a lagging or insulating covering for 39 such boiler furnaces which will hotdisintegrate or deteriorate under high temperatures even after lon continued use,,and which may be readily applied at a reasonable cost for labor and materials.

It is also a further object of the invention to provide this new furnace lagging or insulating means with clean-out openings and closures therefor whereby access may be readily had to the furnace side walls for the purpose of inserting suitable blowers to remove accumulations of dust from the tops of the lower drums or foundation rings and between the water tubes connected therewith. Thus, it is unnecessary to dump the fire and cool down the boiler so that a man may enter the firebox of the furnace in order to re move these accumulations ofdust, ashes or other foreign matter. 1 g With the above and other objects in'view,

the invention consists in the improved ing and insulating material would work away 1928. Serial no, 269,057.

lagging for boiler furnaces, and in the form, construction and relative arrangement of its several parts as will be hereinafter more fully described, illustrated in the accompanying drawings,and subsequently incorporated in the subjoined claims. I

V In the drawings, wherein I have illustrated one simple and practicalembodiment of the invention, and in which similar reference characters desi 'nate corresponding parts throughout the several views,

Figure 1 is aside elevation showing the improved lagging applied to. one side of a locomotive boiler furnace, the lagging being indicated in dot and dash lines on the upper boiler drum and parts of the side wall lagging being broken away;

Fig. '2 is a vertical sectional view taken substantially on the line 2 2 of Fig. 1;

Fig. 3 is a detail horizontal section taken on the line 3'3 of Fig. 2;

Fig. 4 is a vertical sectional view taken on the line 4--l of Fig. 1, and

Fig. 5 isa horizontal section taken on the line 5-5of Fig. 1."

In the use of locomotive boilers of the Mo- Clellonand other types using verticalv water tubes at thefireboxend extending between upper drums and lower drums or foundation rings, it has been the practice to apply fire brick at the outside of the water tubes, over which there is laid magnesia or other insulat- 7 'ing materlal 1n block or plastic form, and

finally the usual sheet metal jacket or covering. This was found to'be unsatisfactory first'on account of its bulk and excessive weight, and secondly, because of the liability of air and smoke leakage. p

In a locomotive of this type built for the Delaware andHudson Railroadc known as the Horatio Allen, to the outside of the vertical water tubes bet-ween the intermediate and rearheaders, there was applied afire felt composition materiaLlargely consisting of asbestos, and then a layer of magnesia msulating material and outside of the latter the metal jacket sheet. However, this also did not give entire satisfaction, as the fire prooffrom the metal parts resulting in leakage openings through which air would be sucked into the furnace chamber which in some cases would nullify combustion efficiency when the engine was working under high pressure and the draft on the furnace was heavy. Also when the steam supplied to the cylinders was shut off and the locomotive was drifting, smoke would pass from the furnace to the exterior through these leakage openings and find its way into the engineers cab. Such openings were more readily formed at the juncture between the lire proofing and the insulation materials and the rear and intermediate header plates.

In a second locomotive of this type built for the Delaware and Hudson Company, and known as the John B. Jervis, the invention of this application was employed and was found to entirely eliminate the disadvantages and deficiencies of the fire proofing and insulating materials for the side walls of the furnace formerly used. This lagging or insulation for the boiler furnace, I have illustrated in one practical example thereof in the accompanying drawings.

Referring to these drawings, 5 designates two upper water and steam drums which extend over the combustion chamber of the furnace, and 6 indicates one of the lower side drums, it being understood of course, that a similar lower drum is provided at the opposite side of the furnace. These upper and lower drums 5 and 6 at each side of the furnace are connected with each other by ver- I tically disposed water and steam circulating tubes 7 which extend substantially the entire length of the firebox and combustion chamber and constitute the side walls thereof. It will be understood, that in so far as the subject matter of this application is concerned, these water and steam circulating conduits between the drums may assume other structural forms.

Over the outer side of each bank of water tubes 7 and in substantial contact therewith a high temperature resisting sheet metal is placed. I have used for this purpose a metal allo Y known under the trade mark of Ascoloy" in thin sheet form, which under tcsthas been found to possess the requisite high temperature resisting qualities. As herein shown, these thin metal alloy sheets are applied in the form of panels 8 of predetermined width so that they may be easily handled, each sheet metal panel being secured to a suitable metal frame structure 9 which includes the vertically extending bars indicated at 10 rigidly secured to the upper and lower drums 5 and 6. These frames also include the angle bars 11 to which the opposite side edges of the sheet metal panels are secured and the angle bars 12 secured to the upper ed es of said panels. These latter bars may e bolted or riveted to the wall of the upper drum 5, while the outwardly projecting flanges of the angle bars 11 on the abuttin edges of adjacent metal sheets 8 are engaged with each other and securely bolted together.

Adjacent to its lower end, each sheet metal panel 8 has one or more circular openings 13 therein and to said sheet around the edge of this opening, a flange on one end of an outwardly extending cast metal bushing 14 is welded or otherwise secured. There is thus provided suitable cleanout openings immediately above the lower drum (5. These openings normally are closed by suitable doors indicated at 15 which preferably are hollow and contain asbestos or other suitable insulating material.

These openings give access to the spaces between the lower ends of the tube so that the to )s of the drums 6 can readily be cleaned After the high temperature resisting metal panels have been applied, these panels are then covered by a suitable fire felt composition sheet material indicated at 16 which also extends upwardly and inwardly over the upper drum 5. The upper ends of the metal sheets 8 follow the curvature of the upper ends of the tubes 7 and therefore, adjacent and above these upper ends of the metal sheets the fire proofing sheet material 16 is spaced from the drum. This space is filled with broken magnesia block grouted in cement as indicated at 17 and a similar filling 18 is preferably placed between the lower ends of the sheet metal panels 8 below the openin s 13 therein and the wall of the lower rum 6.

Upon the fire proofing sheet 16 there is now placed two layers of magnesia blocks indicated at 19. Finally, the outer metal jacketing sheet 21 is applied, said jacketing sheet also preferably extending across and between the upper drums 5 and constituting a. single integral covering for both sides of the boiler. If desired the magnesia or other insulating material may be applied, in either block or plastic form, directly to the metal sheet 8, without using the fire-proofing sheet 16.

As shown in Fig. 4, the lower ends of the extending outwardly as shown at 10 to pro- 4' vide supports upon which a running board extending longitudinally along the side of the locomotive boiler may be conveniently secured. This latter feature however, is not of material importance, as various other means might be devised for mounting or sup porting the running board.

From the foregoing description considered in connection with the accompanying draw ings, it will be seen that a lagging or insulating means of the kind above described enables very tight and secure joints to be made between the inner high temperature resisting metal covering over the water tubes 7 and the sheets of the rear and intermediate vertical headers with which the drums connected. This joint with the header sheets is clearly shown in Fig. of the drawings. Accordingly, it will be evident that the lagging is proof against either the leakage of smoke from the furnace firebox or the ingress of air thereto through the side walls of the furnace. Also by the elimnation of fire brick, the lagging is of minimum bull: and comparatively light in weight.

Whenever necessary, the several clean-out doors may be readily removed or opened so that access can be had through theopenings 13 and a blower inserted to remove accumulations of dust, ashes and other foreign materials from between the lower ends of the water tubes 7 and from the tops of the lower drums 6. Thus, the boiler may be easily maintained at its highest operating efficiency during the operation thereof, and the necessity of dumping the fire and entering the firebox in order to perform such cleaning operations is obviated.

In addition to using the high temperature resisting metal plates for the side walls of the furnace, I also preferably employ similar plates or sheets 22 between the upper drums 5 extending over the additional water circu lating tubes 23 arranged between said drums. Preferably, these metal sheets 22 are slightly arched and upon the same the superposed layers of magnesia blocks 24 are arranged, together with the outer plastic cement layer 25. By arching this sheet 22 and the insulating lagging, a desired bracing efiect is obtained overcoming the tendency of said tion with locomotive boilers of the water tube type.

While I have illustrated an embodiment of the essential features of the invention which. have been successfully carried out 1n actual practice and under severe working conditions, it is nevertheless to be understood that in various minor particulars my present disclosure may be susceptible to more or less modification and change, and I accordingly reserve the privilege of resorting to all such legitimate variations in the form, construction and relative arrangement of the several component parts as may be fairly incorporated in the spirit and scope of the invention as claimed;

I claim:

1. In combination with a boiler furnace having a wall including spaced water c0nductingmembers exposed at the inner side of said wall to direct contact with the products of combustion, high temperature resisting metal plates in direct contact with the outer sides of said water conducting members, a reinforcing frame secured to the outer side of each of said metal plates and rigidly fixed to spaced parts of the boiler structure, and insulating means covering the outer surfaces of said metal plates between the reinforcing frames.

L. In combination with a boiler furnace a" a wall including spaced water and rculating tubes directly exposed to the products of combustion, high temperature resisting metal plates each arranged in direct contact with the outer sides of a series of said tubes, means rigidly connecting said plates with each other, a vertically extending reinforcing frame secured to each of said plates and rigidly fixed at its upper and lower ends to spaced parts of the boiler structure, metal jaclteting sheet supported by said frames in spaced relation to the sheet metal plates, and insulating means interposed between the jacketing sheet, and said nlates and completely filling the spaces between said reinforcing frames.

In testimony that I claim the foregoing as my invention, l have signed my name hereto.

JOHN E. MUHLFELDQ 

